The present invention relates to a four point of contact ball bearing or to a double-row, three-point of contact ball bearing and to means for fixing the bearing parts in position.
Four-point ball bearings of the type indicated are known from Federal Republic of Germany Patent 905 561. In that publication, the races of the bearing rings are developed in the shape of raised regions of balls. The centers of those regions lie on the axis of the bearing. The embodiments shown have spherical regions which have flattenings on both sides. The regions used as inner rings are provided with a bore to receive a shaft. This structure makes necessary the provision of additional attachment surfaces and parts, for instance in the form of the shaft. Since all of these surfaces and parts have manufacturing tolerances, additional inaccuracies result which cannot be accepted upon use of the bearing in swing positioners of disk storages. Since these bearings are very small, with an outside diameter of the outer ring&lt;2 cm, these conditions are even more unfavorable. Although it is possible to produce even highly precise small anti-friction bearings by very precise manufacture, this requires a disproportionately high expense. Furthermore, due to the small size of such bearings, there is still no assurance of accuracy, since frequently, several tolerance deviations are present together. When the deviations add on in the same direction, the bearing is frequently also unusable.